Fuel injection system in petrol engine

The fuel injection system is commonly used in a diesel engine.

In present gasoline injection system is also coming in a petrol engine because following drawbacks of the carburetion.
  • Non-uniform mixture distribution in multi-cylinder engines.
  • Loss of volumetric efficiency.
A gasoline injection system eliminates all these drawbacks.  

The injection of fuel into the SI engine can be done by following methods :
  • Direct injection of fuel into the cylinder
  • Injection of fuel close to the inlet valve
  • Injection of fuel into the inlet manifold
There are two types of the injection system of gasoline systems :
  1. Continuous Injection: In continuous injection, fuel is continuously injected. 
  2. Timed Injection: In timed injection, fuel is injected only during induction stroke. 
Advantages of fuel-injection in SI engines:
  • Increased volumetric efficiency
  • Increase thermal efficiency
  • Low exhaust emissions
  • High-quality fuel distribution

Fuel injection system in diesel engine

The fuel injection system is the most important component of CI engine operation. The system of injection must fulfil the important task of initiating and controlling the process of combustion.

Injection system main purpose is to the preparation of the combustible charge and is same as carburetion.

  • Fuel injection pump such as elevated pressure to high pressure
  • A high-pressure pipe which sends fuel to the injection nozzle
  • Injection nozzle that injects the fuel into the cylinder
  • Feed pump that sucks fuel from the fuel tank
  • Fuel filter which filtrates the fuel
The diesel fuel injection system consists of following below. 

Requirements of an injection system :

  • Accurate metering of the fuel injected per cycle
  • Timing the injection of the fuel  correctly
  • To obtain maximum power, fuel efficiency and clean burning
  • Proper control of the rate of injection
  • Proper atomization of fuel
  • A rapid mixture of fuel and air
  • Uniform distribution of fuel droplets 
  • To supply equal quantities of fuel
  • No lag during the beginning and end of injection

Classification of Injection system :

  • Air injection system 
  • Solid injection system

Air injection system:

Fuel is forced into the cylinder by means of compressed air to very high pressure. 

By varying air pressure, the rate of fuel admitted into the combustion chamber can be controlled.

The fuel is metered & pumped to the fuel valve by a camshaft is driven fuel pump. 

The fuel valve is opened through a mechanical connection operated by the camshaft that controls the injection timing. 

The fuel valve is also connected to a high-pressure airline fed by a multi-stage compressor that supplies air at approximately 60 to 70 bar pressure.

Solid injection system : 

Fuel is injected directly into the combustion chamber without primary atomization is termed as a solid injection. 

It is also termed as a mechanical injection. 

Solid injection system can be classified into four types listed below. 
  • Individual pump & injector
  • Unit injector system
  • Common rail system
  • Distributor system

What is Clutche

The clutch is a mechanical device, which is used to connect and disconnect the source of power from remaining parts of the power transmission system.

Clutch engaged
Clutch disengaged

                                Clutch Disengaged                                                                                     Clutch Engaged   

Clutch transmits engine power to the gearbox and allows the transmission to be interrupted while a gear is selected to move off from a stationary position or when gears are changed while the car is moving.

one of the shafts is typically driven by a motor or pulley, and the other shaft drives another device. one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so that they can either be locked together and spin at the same speed or be decoupled and spin at different speeds.

In a car, a clutch is necessary because the engine spins all the time, but the car wheels don't. In order for a car to stop without killing the engine, the wheels need to be disconnected from the engine somehow. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them.

Clutch disc

The clutch has these three parts sandwiched together creating friction and syncing the engine and the wheels(through gearbox).
To represent the engine we have the flywheel which is attached to the crank and it moves with the engine.
  • The clutch disc
Between the flywheel and the pressure plate is the clutch disc. 
The clutch disc has friction surfaces similar to a brake pad on both sides that make or break contact with the metal flywheel and pressure plate surfaces, allowing for smooth engagement and disengagement.
  • The Pressure Plate
When the clutch pedal is depressed, the pressure plate releases, allowing itself and the flywheel to spin independently of the disc, which prevents torque from being transmitted from the engine to the gearbox. Generally made of cast iron or steel, the pressure plate uses a diaphragm-type spring to apply force against the disc once engaged, which is fastened to the assembly by a series of straps.
  • Throwout Bearings
The throwout bearing sits against the pressure plate in either a push-style or pull-style arrangement that compresses the diaphragm and releases the disc when the clutch pedal is depressed. Once force is applied, the diaphragm releases tension, allowing the disc to spin independently of the assembly.
Simply adding additional clutch plates will make the system engage much faster and more efficiently the problem is that the outer pads will wear out fast.

Mainly clutches are divided into 2 parts:

  1. Friction clutches and
  2. Fluid flywheel

Friction clutches:

These clutches works on the principle of friction exist in between two rotating shafts when they come in contact with each other.

Fluid flywheel:

Fluid flywheel clutches works on transfer of energy from one rotor to the other by means of some fluid.

Types of friction clutches:

  1. Cone clutch
  2. Single plate clutch
  3. Multi-plate clutch
  4. Semi-centrifugal clutch
  5. Centrifugal clutch
  6. Hydraulic  clutches
  7. Electromagnetic clutches
1. Cone clutch: Cone clutches are nothing, but frictional clutches with conical surfaces. The area of contact differs from normal frictional surfaces. 

The conical surface provides a taper, which means that while a given amount of actuating force brings the surfaces of the clutch into contact really slowly, the pressure on the mating surfaces increases rapidly.  

2. Single plate clutch: These clutches are having a single frictional surface to transmit the power between two shafts. These clutches are larger in size when compared to multi-plate clutches of the same transmission capacity.

3. Multi-plate clutches: These clutches are used in the applications where you don't have enough space to install large single-plate clutches. They provide a better coefficient of friction, as the surface area is increased due to the presence of multiple plates.

4. Centrifugal clutches: Centrifugal and semi-centrifugal clutches Works on the principle of centrifugal force and transmits the power between the shafts when a certain speed is attained by the shafts.

5. Hydraulic clutches: As the name itself suggests, operated by hydraulic pressure.

6. Electromagnetic clutches: These clutches engage the theory of magnetism on to the clutch mechanisms. The ends of the driven and driving pieces are kept separate and they act as the pole pieces of a magnet. When a DC current is passed through the clutch system, the electromagnet activates and the clutch is engaged.

What is difference between dry clutch and wet clutch?

The clutch which is a simple device which facilitates hassle-free torque transfer from the engine to gearbox and ultimately to the drive wheels. A wet clutch is called wet because it is actually wet with engine oil and the dry clutch does not live in an oil bath. Now let we check it out the difference between dry and wet clutch. 

Difference : 
  • A dry clutch has a higher coefficient of friction whereas wet clutch coefficient of friction is reduced due to oil.
  • Torque capacity of dry clutch is high as compared to the wet clutch of the same dimension.
  • Heat dissipation is more difficult in the dry clutch and wet clutch lubricating oil carries away the frictional heat.
  • Wear and tear are less in the wet clutch as compare to dry clutch.
  • The sound in the dry clutch is more as compared to the wet clutch and goes on increasing as the clutch goes on wearing out. 
  • The engagement in the wet clutch is smoother than a dry clutch.
  • It is necessary to prevent contamination due to moisture or nearby lubricated machinery, by providing seals in dry clutch whereas that is not necessary for a wet clutch.
  • The life of dry clutch is less as compared to a wet clutch. 

What is Machine Design

Introduction :

Machine design is the use of scientific principles, technical information and imagination in the description of the machine or any mechanical system to perform a specific function with maximum economy and efficiency.

While any design takes part below features are take care :
  • A designer uses the principle of basics and engineering science.
  • The designer has technical information on basic elements of a machine.
  • The designer uses his skill and imagination to produce a configuration.
  • The final outcome of the design process consists of the description of the machine.
  • A design is created to satisfy the need of the customer.

The basic procedure of machine design :
  • Market survey
  • Define the specifications of the product
  • Study alternative mechanics for product
  • Prepare the general layout of the configuration
  • Design individual components
  • Prepare assembly 

The Purpose of Machine Design :

The knowledge of machine design helps the designers as follows:
  • To select proper materials and best-suited shapes
  • To calculate the dimensions based on the loads on machines and strength of the material
  • Specify the manufacturing process for the manufacture of the designed component of the machine or the whole machine.

Machine Design is the application of mathematics, kinematics, statics, dynamics, mechanics of materials, engineering materials, mechanical technology of metals and engineering drawing. It also involves the application of other subjects like thermodynamics, electrical theory, hydraulics, engines, turbines, pumps etc. Machine drawing is the integral part of the machine design since all the components or the machines that have been designed should be drawn to manufacture them as per the specifications. Without machine drawing the subject of the machine design is incomplete.

Machine Design

What is Fits

Fits :
Fits is when two parts are assembled the difference between their sizes before assembly is called fit.

There are mainly classify three group :
  • Clearance Fit - Always provides a positive clearance
  • Interference Fit - Always provides a positive interfearance over a whole range of tolerance.
  • Transition Fit - Which may provide either a clearance or interfearance 

What is Tolerance

Tolerance :

The components are manufactured that all lie in between maximum and minimum limits.

The basic dimensions is called the normal or basic size while difference between the two limits is called permissible tolerance.

Tolerance is defined as permissible variation in the dimension of the components.

Tolerance have two system of specifications :
  • Unilateral
  • Bilateral
In unilateral one tolerance is zero while other takes care of all permissible variation in the basic size.

In bilateral tolerance the two tolerance are often equal.

In machine design there are two basic system for giving
tolerance to the shaft or hole :
  • Hole basis system
  • Shaft basis system
According to the Bureau of Indian Standards tolerance is specified by an alphabet, capital or small followed by number e.g. G8 or h6

There are eighteen grades of tolerances : IT1, IT2 upto IT18
The letters of symbol IT stand for INTERNATIONAL TOLERANCE GRADE

Basic Procedure of Design

The basic procedure of machine design :
  • Market survey
  • Define specifications of the product
  • Study alternative mechanics for product
  • Prepare the general layout of the configuration
  • Design individual components
  • Prepare assembly

The basic procedure of machine elements :
  • Specify the function of an element
  • Determine forces acting on an element
  • Select suitable material for an element
  • Determine the failure mode of an element
  • Determine geometric dimensions of an element
  • Modify dimensions for assembly
  • Prepare a working drawing element

What is lubrication

To supply lubricating oil between the moving parts is simply termed as lubrication.
Friction is the force that resists relative motion between two bodies in contact. If friction didn't exist nothing would ever stop moving for this reason lubrication is necessary.

The function of lubricants is to reduce friction and heat. 

Purpose of Lubrication :
  • To reduce the frictional forces between the parts having relative motion 
  • To reduce the wear and tear of moving parts
  • Corrosion prevention
  • To cool the surfaces by carrying away the heat generated due to friction
  • To seal a space adjoining the surfaces such as piston rings and cylinder linear
  • To absorb the shocks 
  • Cleaning agent 
  • To help the piston rings to seal the gases inside the piston cylinder
  • Increase fuel economy by providing low friction surfaces

Advantages of lubrication in the engine parts :

  • Higher efficiency 
  • longer life
  • better reliability
  • less money spent on maintenance 

Parts of Engine Requires Lubrication :

The main parts of the engine which need lubrication are:
  • Main crankshaft bearings.
  • Big end bearings or crank pin.
  • Gudgeon in bearings.
  • Piston rings and cylindrical walls.
  • Timing gears. 
  • Camshaft and camshaft bearings.
  • Valve mechanism
  • Valve guide, valve tappets, rocker arms.
  • Governor and
  • Water pump bearing.
Any substance introduced between two moving or sliding surface with a view to reducing the frictional resistance between them is called lubricants.

Types of Lubricants :

Lubricants are at following three types.

1. Solid: graphic, mica etc
2. Semi-solid: grease
3. Liquid: mineral oil, vegetable oil, animal oil etc.

Graphite is often mixed with oil to lubricate automobile spring. Graphite is also used as a cylinder lubricant.

Grease is used for chassis lubrication.

Mineral oils are almost used for engine lubrication.
Grade of lubricants: Generally, lubricating oils are graded by their SAE (society of automotive engineers) viscosity number. 
5w,10w,20w SAE number lubricating oil are for winter use.
20,30,40 SAE number lubricating oil is for summer use.

IMEP full form

What is full form of IMEP ?

Answer :
  • Indicated Mean Effective Pressure
The average pressure produced in the combustion chamber during the operating cycle.


IMEP = Net work of cycle / V1 - V2

Full Form of Education Degree and Related Terms

BA - Bachelor of Arts

BCA - Bachelor of Computer Applications   

B.Com - Bachelor of Commerce

BE - Bachelor of Engineering

BHMS - Bachelor of Homoeopathic Medicine and Surgery

B.Ed - Bachelor of Education 

BPEd - Bachelor of Physical Education

BSE - Bachelor of Software Engineering

B.Tech - Bachelor of Technology

BAMS - Bachelor of Ayurvedic Medicine and Surgery

BBA - Bachelor of Business Administration

BBM - Bachelor of Business Management

BMS - Bachelor of Management Studies

CV - Curriculum Vitae

CS - Company Secretary

D2D - Diploma to Degree 

DMLT - Diploma in Medical Laboratory Technology

DPT - Doctor of Physical Therapy

EPGPM - Executive Post Graduate Programme

FPM - Fellow Program in Management

GPA - Grade Point Average

HSC - Higher Secondary Certificate

IQ - Intelligence Quotient

ISC - Indian School Certificate

LLB - Bachelor of Laws

LLM - Master of Laws

MBA - Master of Business Administration

MBBS - Bachelor of Medicine and Bachelor of Surgery

MCOM - Master in Commerce

MD - Doctor of Medicine

MS - Master of Science

M.Sc. - Master of Science

M.Tech - Master of Technology

MSCIT - Master of Science in Information Technology

M.Phil - Master of Philosophy

MCA - Master of Computer Applications

MA - Master Of Arts

PGDM - Post Graduate Diploma in Management

PGP - The post-graduate program

PGPEM - Post Graduate Programme in Enterprise Management

PGPBM - Post Graduate Programme in Business Management

PGPWE - Post Graduate Programme for Working Executive

PGPPM - Post Graduate Progamme in Public Policy and Management

PGPSM - Post Graduate Programme in Securities Markets

PGDHRM - Post Graduate Diploma in Human Resource Management

PGPEX - Post Graduate Programme for Executives

PG - Postgraduate

PGDCA - Post Graduate Diploma in Computer Application

PhD - Doctor of Philosophy 

PGP ABM - Post Graduate Program for Agri Business Management

RTI - Right To Information

SSLC - Secondary School Leaving Certificate

UGC - University Grants Commission

UG - Undergraduate 

i.e - "that is"

Full Form of Organization

BMW - Bavarian Motor Works

NASA - National Aeronautics Space Administration 

IBM - International Business Machines

KFC- Kentucky Fried Chicken

UNICEF - United Nations Children's Fund

DLF - Delhi Land and Finance

ISO - International Organization for Standards

HTC - High Tech Computer

CRPF - Central Reserve Police Force

FSSAI - Food Safety and Standards Authority of India

JCB - Joseph Cyril Bamford

HTC - High Tech Computer

ITC - Indian Tobacco Company - Indian Trade Centre

IBPS - Institute of Banking Personnel Selection

CEO - Chief Executive Officer

SOS - Save Our Souls

NGO - Non-Governmental Organization

IEEE - Institute of Electrical and Electronics Engineers

CID - Criminal Investigation Department

RAW - Research and Analysis Wing

LG - Lucky Goldstar

ADIDAS - Adolf "Adi" Dassler         

WIPRO - Western India Products

UNESCO - United Nations Educational, Scientific and Cultural Organization

DHL - Dalsey Hillblom Lynn

WWF - World Wild Fund - World Wrestling Federation 

FBI - Federal Bureau of Investigation 

CBI - Central Bureau of Investigation

BBC - British Broadcasting Corporation 

RTO - Road Transport Office

PSU - Public Sector Undertaking

PVR - Priya Village Roadshow

BSNL - Bharat Sanchar Nigam Limited

MTNL - Mahanagar Telephone Nigam Limited

BHEL - Bharat Heavy Electricals Limited

NATO - North Atlantic Treaty Organization

IRCTC - Indian Railways Catering and Tourism Corporation

BBC - British Broadcasting Corporation

TVS - Trichur Vengaram Sundaram

CRPF - Central Reserve Police Force

CISF -  Central Industrial Security Force

FSSAI - Food Safety and Standards Authority of India

NDA - National Defence Academy

NSDL - National Securities Depository Limited

ONGC - Oil and Natural Gas Corporation

L&T - Larsen & Toubro